Circuit-disabling device for electric lamps



3, 1929. R. T. HOSKING 1,724,654

CIRCUIT DISABLING DEVICE FOR ELECTRIC LAMPS Filed March 9, 1928 Til-WW F/LAMENT Wl/PE BULB ' 6: IN VEN TOR BY ZC/JHRU 7. HOS/(ING- d ATTORNEY Patented Aug. 13, 1929.

UNITED STATES 1,724,654 PATENT OFFICE.

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' or cnrcxeo, rumors, A CORPORATION or rumors GIBOUIT-DISABLING DEVICE FOR ELECTRIC LAMPS.

Application filed March 9, 1928. Serial No. 860,388.

This invention relates to improvementsan lamps of the incandescent type fitted with screw sockets, the object of the lnvention being to provide means for automatically spoiling the lamp by rupturing the filament wire at a place within the bulb head whenever the lamp is turned in the unscrewing direction,'and to do this without in any way locking or even appreciably retarding the unscrewing movement, as distinguished from the usual lamp lock whose function is to lock and prevent unscrewing untll after a latch or similar device has been released by mechanism that has to be worked independently of the unscrewing of the lamp.

With the foregoing and certain other objects in view, which will appear later in the specification, my invention comprises the devices described and claimed and the equivalents thereof. I

In the drawings Fig. 1 is a longitudinal sectional view showing my improvement in position on a lamp socket.

Fig. 2 is a side view of the corresponding socket liner.

Fig. 3 is a side view of the bulb head shown in section in Fig. 1.

Fig. 4 is a similar view showing a modified form of device for exposing the loop of filament wire.

Fig. 5 is a transverse section on the line 55 of Fig. 1, showing the manner in which the projection of the filament leader wire is finlgaged by the yieldable stop on the socket Fig. 6 is an enlarged fragmentary sectional view of the bulb head, showing the exposed loop of the filament wire.

In the drawings there is shown an ordinary incandescent lamp consisting of the usual glass globe 1 containing the filament 2 and an externally threaded metal shell or bulb head 3 secured to the globe by means of a cement filling 4.

The filament 2 iselectrically connected to the threaded shell of the bulb head 3 by means of a wire filament terminal 5 that extends through the cement filling and is soldered or otherwise secured, as at 6, to the metal shell of the bulb head. There is also the usual internally threaded socket liner 7 of sheet metal, into which the bulb head is threaded.

So far the structure described is that of the ordinary electric lamp to which is added my present invention, as follows:

The filament wire 5, instead of passing down through the cement filling 4 of the bulb head directly to its point of attachment by solder, is passed out through an opening 8 provided in the shell of the bulb head and back in again through another opening 9, thus forming a wire loop 10 external to the bulb head. The two holes 8, 9 are preferably made in the side walls of a thread groove 11.

' The wire preferably has a score 12 formed in it within the bulb head, so that pulling the wire out as indicated by the dotted line in Fig. 6, will result in rupturing the wire at the score 12 within the bulb head.

My invention provides means such as an internal projection 13 on the interiorly threaded wall of the metal socket liner, this projection being arranged so that the exposed loop 10 will not be interfered with while the lamp is being screwed into the socket liner, but when the socket liner is unscrewed the wire loop 10 of the bulb head catches on the internal projection 13.

of the socket liner. Farther rotation of the bulb head draws the loop 10 farther out through the hole 8 and ruptures the filament wire 5 at its weakened or scored point 12 inside the bulb head. This does not materiallyifiinterfere with unscrewing the lamp or removing it from the socket, but the lamp is spoiled by unscrewing and cannot be used agaln.

In its preferred form the internal stop member 13 on the socket liner is an inwardly projecting yieldable finger, shown in Figs. 2 and 5, made by cutting away the metal of the socket liner to form a tongue which is sprung inwardly, as shown in Fig. 5. This yieldable stop member 13, as already stated, permits the protruding part of the filament wire to pass freely underneath it in one direction, butcauses the wire to be engaged and held back when the bulb is turned in the unscrewing direction, whereby farther turning of the socket head automatically draws the wire outward and fractures it at the score. This automatic rupture of the filament wire by unscrewing the lamp without mechanically locking the bulb tofore produced, constitutes the essential function and operating mode of the invention.

In the form shown in Fig. 3 the filament wire is run loosely through the holes 8, 9 in the bulb head which may be openings punched for the purpose, but the openings are preferably in the form shown in Fig. 4, where they are connected together to form a tongue 14 between them. I prefer this latter construction because it enables the filament wire to be put in place for soldering more easily and quickly than can be done by threading it through the two holes shown in Fig. 3. However, any other form of opening is permissible because the essential thing is that a part of the filament wire shall pro ject outside the bulb head and be arranged to become engaged by a fixed stop on the socket liner so that farther rotation of the bulb head in the unscrewing direction will pull on the wire to rupture it at a weakened point inside the bulb head.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In an incandescent lamp having an internally threaded socket liner and an externally threaded interengaging bulb head with a filament leader wire therein, one end of said wire secured to the wall of the bulb head, means for automatically rupturing said filament leader wire at a place within the bulb head, said means comprising a score in the wire within the bulb head, the wire being arranged so a part of its length protrudes outside the threaded wall of the bulb head, extending freely through an opening in said wall, and an inwardly projecting yieldable stop member on said socket liner adapted to permit the said protruding part of the wire to pass freely inone direction, but to be engaged and held back when the bulb head is turned in the unscrewing direction, whereby farther turning of the socket head draws the wire outward and fractures it at the score.

2. In an incandescent lamp having an internall threaded socket liner and an externally threaded interengaging bulb head with a filament leader wire therein, one end of said wire secured to the wall of the bulb head, means for automatically rupturing said filament leader wire at a place within the bulb head, said means comprising a weakened place in the wire within the bulb head, the wire arranged so a part of its length protrudes outside the threaded Wall of the bulb head, extending freely through an opening in said wall, and means integral with said socket liner adapted to engage and hold said protruding wire so that farther turning of the socket head draws the wire therefrom and fractures it.

3. An electric lam wherein the filament wire of its exterior-lg threaded bulb head protrudes and spans the s ace between threads thereof, and its interiorly threaded socket lining is provided with a co-operating yieldable inwardly projecting stop member that is engaged by the said protruding wire when the lamp is turned to unscrew, where by upon farther turning the wire is held back and automatically ruptured within the bulb head, spoiling the lamp.

4. An electric lam wherein the filament leader wire of its bulli head protrudes therefrom and its socket linin is provided with means adapted to engage and hold back said wire, whereby the wire is automatically ruptured at a place within the bulb head to spoil the lam while the lamp is being removed from tiie socket lining.

5. An electric lamp wherein the filament leader wire of its exteriorly threaded bulb head protrudes therefrom and the interiorly threaded socket lining is provided with& cooperating projection that is engaged by the said protruding wire, whereby the wire is held back and automatically ruptured to spoil the lamp while the lamp is being unscrewed from the socket linin 6. An electric lamp wherein the filament wire of its exteriorly threaded bulb head protrudes and spans the space between threads thereof, for the purposes set forth.

7. A structure as claimed in claim 6 wherein the wire is formed with a score at a predetermined breaking point.

In testimony whereof, I afiix my signature.

RICHARD T. HOSKING. 

